Conclusion:

It was a real joy testing the Icy Dock MB080U3S-1SB Blizzard and MB559U3S-1S Ultra Slim Enclosures. They are very well made and durable, which means that you will not have to worry about small thin plastic pieces breaking off accidently. Surprisingly even with the bulky size of the Blizzard enclosure it fits well on a desk and does not take up too much room. I would have like the Blizzard's internal LED light to be a bit brighter by the switch or have the LEDs placed more up front to see the blue/red glow, but that is more just personal preference. Others may like the dimmer look.

When it came to the cooling efforts of the Blizzard however; with its bulky and unique design, the drive under load stayed approximately 2 °C cooler, which is proved the design features work. To comment on the Ultra Slim's design as well, the sleek and compact size allows you to place this enclosure anywhere even on top of a tower or, as I like it, underneath a monitor. The removable tray allows you to hot swap drives, providing your motherboard supports it and you are setup in AHCI mode. Installation for both were a breeze. The Blizzard was completely tool-less and takes only a few seconds to add or remove a hard drive. The Ultra Slim, even with the few screws you need to mount the drive to the sled, is practically tool-less as well considering you can have multiple sleds ready to swap out.

The performance of both enclousres were very close to each other. A few times they even over took the comparison drives in the eSATA portions. If you are in the market for a new external enclosure I highly suggest looking into these. If temperature is a factor then you cannot go wrong at all with the Icy Dock Blizzard especially for higher PRM drives such as the Raptors, which put off a lot of heat. Other than a few preference changes there are no drawbacks to these two enclosures and end users will not be disappointed.